[docs] Doxygen updates for openthread.io reference documentation (#2271)

include/openthread/openthread.h

@@ -57,6 +57,8 @@ extern "C" {
  *
  * @{
  *
+ * @defgroup api-types Types
+ *
  * @defgroup api-execution Execution
  *
  * @{

include/openthread/platform/logging.h

@@ -57,7 +57,7 @@ extern "C" {
 /**
  * Log levels.
  *
- * Implimentation note: These exist as defines (not enums) so that
+ * Implementation note: These exist as defines (not enums) so that
  * embedded code can remove code at compile time via if/else/endif
  */
 

include/openthread/types.h

@@ -68,6 +68,16 @@ extern "C" {
 #endif /* CONTAINING_RECORD */
 #endif /* _WIN32 */
 
+/**
+ * @addtogroup api-types
+ *
+ * @brief
+ *   This module includes API types
+ *
+ * @{
+ *
+ */
+
 /**
  * This type represents the OpenThread instance structure.
  */
@@ -1125,6 +1135,10 @@ typedef enum otLogRegion
     OT_LOG_REGION_CLI      = 14, ///< CLI
 } otLogRegion;
 
+/**
+ * @}
+ *
+ */
 
 #ifdef __cplusplus
 }  // extern "C"